Reaction mass of aluminium fluoride and chromium trifluoride and nickel difluoride

Toxicity to aquatic algae and cyanobacteria

Description of key information

Toxicity to aquatic algae: 
   -   EbC50 (72h) = 197 µg/L ; NOEC = 22.8 µg/L (OECD TG 201)
   -   ErC50 (72h) = 313.6 µg/L ; NOEC = 83.3 µg/L (OECD TG 201)

Additional information

One key study is available for this endpoint. The acute toxicity (growth inhibition) of the test item REACTION MASS OF AlF3/CrF3/NiF2 to the freshwater algae Pseudokirchneriella subcapitata was assessed by the GRL (2010) according to the OECD Guideline 201 and incompliance with OECD (2004) Good Laboratory Practice standards. Based on the results of preliminary test, the definitive test was performed with a concentration range forming a geometric progression with a factor of 2.15: 0.05, 0.1, 0.16, 0.25, 0.40, 0.63 and 1% of a saturated stock solution of ground REACTION MASS OF AlF3/CrF3/NiF2 in dilution water.

 

Analytical monitoring has been performed at the beginning and at the end of the exposure period. It consists in ionic chromatography of “fluorides”. In order to calculate the correlation factor between fluorides concentration and the concentration of metallic fluorides in the samples, analysis of aluminium, chromium and nickel were performed on the stock solution by ICP-MS. An average factor allowing to pass from fluorides concentration to the test item (metallic fluorides) concentration can be estimated to 2.24. This calculation allows to express EC₅₀ as REACTION MASS OF AlF3/CrF3/NiF2.The concentration of fluoride ions didn’t remain constant over the exposure period. So, estimation of effective concentrations (EC₅₀) was based on geometric average values of initial and final concentrations of fluoride ion F^-or of corresponding test item.

 

Algae (at an initial cell concentration of 10⁴cells/mL) were exposed under static conditions to the test item. These organisms obtained from the Culture Centre of Algae and Protozoa (Ambleside, UK) were incubated at 23 ± 1 °C and constantly illuminated by 8 fluorescent tubes between 6,000 and 10,000 lux over the exposure period. During the assay, the toxic effect measured and recorded after 0, 24, 48 and 72 hours was the inhibition of cellular multiplication. The presence of insoluble material was also checked.

 

No precipitation was observed at the end of the test. Microscopic observation confirmed that the algae appeared normal at the end of the test.The biomass in the control cultures increased exponentially by a factor of 121 (corresponding to a specific growth rate of 1.598 day^-1) within the 72-hour test period.

 

Exposure of the freshwater algae Pseudokirchneriella subcapitata to the test item REACTION MASS OF AlF3/CrF3/NiF2 resulted in 72h E_bC₅₀(cell growth) and 72h E_rC₅₀(growth rate) of 197 and 313.6 µg/L respectively.

 

72 hour no observed effect concentrations based on cell growth and on growth rate were 22.8 and 83.3 µg/L respectively.

 

Based on the results of this study, the test item REACTION MASS OF AlF3/CrF3/NiF2 is considered asvery toxicto the aquatic organisms tested in accordance with the Directive 67/548/EC.